diff --git a/matweb/rest_api.py b/matweb/rest_api.py
index 5784bec..49e7183 100644
--- a/matweb/rest_api.py
+++ b/matweb/rest_api.py
@@ -98,8 +98,10 @@ class APIClean(Resource):
     @swag_from('./oas/remove_metadata.yml')
     def post(self):
         if 'file' not in request.files:
-            current_app.logger.error('Clean - No file part')
-            abort(400, message='No file part')
+            current_app.logger.error(
+                'Clean - File part missing: Multipart filename and non-chunked-transfer-encoding required'
+            )
+            abort(400, message='File part missing: Multipart filename and non-chunked-transfer-encoding required')
 
         uploaded_file = request.files['file']
         if not uploaded_file.filename:
diff --git a/test/test_api.py b/test/test_api.py
index 3cc44a6..91ea043 100644
--- a/test/test_api.py
+++ b/test/test_api.py
@@ -486,7 +486,10 @@ class Mat2APITestCase(unittest.TestCase):
             ),
             follow_redirects=False
         )
-        self.assertEqual(r.get_json()['message'], 'No file part')
+        self.assertEqual(
+            r.get_json()['message'],
+            'File part missing: Multipart filename and non-chunked-transfer-encoding required'
+        )
         self.assertEqual(r.status_code, 400)
 
         r = self.app.post(